LOS ANGELES (AP) -- Students at Los Angeles schools will be shielded from prosecution and sent to administrators for low-level offenses, officials will announce Tuesday, in the latest rollback to tough discipline policies across the U.S. that critics say are miring too many young minorities in the criminal justice system.

Rather than face arrest or citations for violations like possessing alcohol or marijuana on school property, students in could be referred to off-site counseling centers or sent to the principal's office. The reforms, to be announced by the Los Angeles Unified School District, represents a shift that activists, educators and justice officials say will prevent students, especially minorities, from becoming trapped in the criminal justice system.

"Zero tolerance" policies, instituted across the U.S. in the 1970s and 1980s, were intensified in the wake of the 1999 school shooting in Columbine, Colorado, where two students killed 12 classmates and a teacher before killing themselves. The trend away from strict punishments, seen in school districts from California to Florida, gained ground in January when the Obama administration issued reforms that emphasize conflict resolution and classroom management over arrests and citations.

The sheer size of the Los Angeles district -- the second-largest in the U.S. -- is what makes its move groundbreaking. With more than 640,000 students at nearly 1,100 schools, Los Angeles is among the largest school districts whose police have adopted a policy of less punitive discipline.

"This is a huge breakthrough," said Zoe Rawson, a legal advocate with the Community Rights Campaign, a grass-roots organization that lobbied the school district police to adopt the reforms. Rather than face the "permanent hole" of the criminal justice system, Rawson said, "a guidance counselor will be there to sit down and be there with a young person and their family."

School board member Monica Garcia said the policy change was about being "appropriate" - and said offenses that are considered "category one" like brandishing a weapon or selling drugs don't fall under the policy changes.

Under the new policy, which is in place for the current school year, if a student is caught fighting, vandalizing school property or carrying alcohol, a school police officer must follow a step-by-step formula directing students to either on- or off-campus interventions. Previously, such offenses would send a student to court or probation.

Students possessing less than an ounce of marijuana will be sent to an off-site resource center. How to deal with repeat offenses isn't spelled out in the policy to give more latitude to officers and school officials.

"There's plenty of evidence we are tough. This is about changing behavior," Garcia said. "We're acknowledging we have young people who need guidance and an opportunity to learn from their mistakes."

Scaling back officers' role in schools will eliminate racial disparities in student arrest rates, activists and educators said.

"It really is in low-income communities of color that we've seen this increase in law enforcement presence," said Ruth Cusick, an attorney with pro bono law firm Public Counsel who helped negotiate the policy changes with the district's police force.

Of the approximately 9,000 arrests and tickets issued to students in the 2011-2012 school year, 93 percent involved black and Latino students, according to data provided by the district to the Labor/Community Strategy Center.

According to district data from the 2013-14 school year, black students accounted for about 11 percent of Los Angeles' student population, but they made up about one-third of those suspended.

Los Angeles entered a voluntary agreement with the Department of Education in 2011 after an investigation concluded the district had carried out "inequitable and disproportionate" practices.

In recent years, the district has scaled back harsh punishments. In 2013, the district became the first in the nation to ban suspensions of defiant students. And in 2012, it began diverting truant students to counseling at off-site resource centers rather than issue tickets.

Jim Eichner, the managing director of programs for Washington, D.C.-based civil rights group Advancement Project, praised the end of "excessively harsh discipline" for low-level misconduct.

"Disruptive behavior is sometimes par for the course for students who are learning to behave properly," Eichner said.

Regarding criticism that educators are going soft on unruly students, Eichner said the types of treatment students undergo at school or off-site centers are effective and challenging.

"More restorative practices -- that's actually really being tough on kids because it makes kids face up to their behavior," Eichner said.